For the cream cheese glaze: Add the confectioners' sugar
to the bowl of a stand mixer
. Break up the cream cheese, add it to the bowl and then add the milk and corn syrup
. Mix on low speed for 1 minute. Raise to medium speed and mix for another minute. Scrape down the bowl, making sure there are no clumps of sugar on the bottom. Mix on high speed until smooth, 2 minutes.
For the everything topping: Preheat the oven to 375 F. Line a baking sheet with parchment paper.
Toss the black sesame seeds, white sesame seeds, pepitas, poppy seeds, garlic flakes and salt in the melted butter, then spread on the prepared baking sheet. Transfer to the oven and cook until golden brown, 10 to 12 minutes.
Dip the doughnuts into the cream cheese glaze and sprinkle with everything topping.